/**
 * @author mrdoob / http://mrdoob.com/
 */

THREE.OBJLoader = (function ()
{

    // o object_name | g group_name
    var object_pattern = /^[og]\s*(.+)?/;
    // mtllib file_reference
    var material_library_pattern = /^mtllib /;
    // usemtl material_name
    var material_use_pattern = /^usemtl /;

    function ParserState()
    {

        var state = {
            objects: [],
            object: {},

            vertices: [],
            normals: [],
            colors: [],
            uvs: [],

            materialLibraries: [],

            startObject: function (name, fromDeclaration)
            {

                // If the current object (initial from reset) is not from a g/o declaration in the parsed
                // file. We need to use it for the first parsed g/o to keep things in sync.
                if (this.object && this.object.fromDeclaration === false)
                {

                    this.object.name = name;
                    this.object.fromDeclaration = (fromDeclaration !== false);
                    return;

                }

                var previousMaterial = (this.object && typeof this.object.currentMaterial === 'function' ? this.object.currentMaterial() : undefined);

                if (this.object && typeof this.object._finalize === 'function')
                {

                    this.object._finalize(true);

                }

                this.object = {
                    name: name || '',
                    fromDeclaration: (fromDeclaration !== false),

                    geometry: {
                        vertices: [],
                        normals: [],
                        colors: [],
                        uvs: []
                    },
                    materials: [],
                    smooth: true,

                    startMaterial: function (name, libraries)
                    {

                        var previous = this._finalize(false);

                        // New usemtl declaration overwrites an inherited material, except if faces were declared
                        // after the material, then it must be preserved for proper MultiMaterial continuation.
                        if (previous && (previous.inherited || previous.groupCount <= 0))
                        {

                            this.materials.splice(previous.index, 1);

                        }

                        var material = {
                            index: this.materials.length,
                            name: name || '',
                            mtllib: (Array.isArray(libraries) && libraries.length > 0 ? libraries[libraries.length - 1] : ''),
                            smooth: (previous !== undefined ? previous.smooth : this.smooth),
                            groupStart: (previous !== undefined ? previous.groupEnd : 0),
                            groupEnd: -1,
                            groupCount: -1,
                            inherited: false,

                            clone: function (index)
                            {

                                var cloned = {
                                    index: (typeof index === 'number' ? index : this.index),
                                    name: this.name,
                                    mtllib: this.mtllib,
                                    smooth: this.smooth,
                                    groupStart: 0,
                                    groupEnd: -1,
                                    groupCount: -1,
                                    inherited: false
                                };
                                cloned.clone = this.clone.bind(cloned);
                                return cloned;

                            }
                        };

                        this.materials.push(material);

                        return material;

                    },

                    currentMaterial: function ()
                    {

                        if (this.materials.length > 0)
                        {

                            return this.materials[this.materials.length - 1];

                        }

                        return undefined;

                    },

                    _finalize: function (end)
                    {

                        var lastMultiMaterial = this.currentMaterial();
                        if (lastMultiMaterial && lastMultiMaterial.groupEnd === -1)
                        {

                            lastMultiMaterial.groupEnd = this.geometry.vertices.length / 3;
                            lastMultiMaterial.groupCount = lastMultiMaterial.groupEnd - lastMultiMaterial.groupStart;
                            lastMultiMaterial.inherited = false;

                        }

                        // Ignore objects tail materials if no face declarations followed them before a new o/g started.
                        if (end && this.materials.length > 1)
                        {

                            for (var mi = this.materials.length - 1; mi >= 0; mi--)
                            {

                                if (this.materials[mi].groupCount <= 0)
                                {

                                    this.materials.splice(mi, 1);

                                }

                            }

                        }

                        // Guarantee at least one empty material, this makes the creation later more straight forward.
                        if (end && this.materials.length === 0)
                        {

                            this.materials.push({
                                name: '',
                                smooth: this.smooth
                            });

                        }

                        return lastMultiMaterial;

                    }
                };

                // Inherit previous objects material.
                // Spec tells us that a declared material must be set to all objects until a new material is declared.
                // If a usemtl declaration is encountered while this new object is being parsed, it will
                // overwrite the inherited material. Exception being that there was already face declarations
                // to the inherited material, then it will be preserved for proper MultiMaterial continuation.

                if (previousMaterial && previousMaterial.name && typeof previousMaterial.clone === 'function')
                {

                    var declared = previousMaterial.clone(0);
                    declared.inherited = true;
                    this.object.materials.push(declared);

                }

                this.objects.push(this.object);

            },

            finalize: function ()
            {

                if (this.object && typeof this.object._finalize === 'function')
                {

                    this.object._finalize(true);

                }

            },

            parseVertexIndex: function (value, len)
            {

                var index = parseInt(value, 10);
                return (index >= 0 ? index - 1 : index + len / 3) * 3;

            },

            parseNormalIndex: function (value, len)
            {

                var index = parseInt(value, 10);
                return (index >= 0 ? index - 1 : index + len / 3) * 3;

            },

            parseUVIndex: function (value, len)
            {

                var index = parseInt(value, 10);
                return (index >= 0 ? index - 1 : index + len / 2) * 2;

            },

            addVertex: function (a, b, c)
            {

                var src = this.vertices;
                var dst = this.object.geometry.vertices;

                dst.push(src[a + 0], src[a + 1], src[a + 2]);
                dst.push(src[b + 0], src[b + 1], src[b + 2]);
                dst.push(src[c + 0], src[c + 1], src[c + 2]);

            },

            addVertexLine: function (a)
            {

                var src = this.vertices;
                var dst = this.object.geometry.vertices;

                dst.push(src[a + 0], src[a + 1], src[a + 2]);

            },

            addNormal: function (a, b, c)
            {

                var src = this.normals;
                var dst = this.object.geometry.normals;

                dst.push(src[a + 0], src[a + 1], src[a + 2]);
                dst.push(src[b + 0], src[b + 1], src[b + 2]);
                dst.push(src[c + 0], src[c + 1], src[c + 2]);

            },

            addColor: function (a, b, c)
            {

                var src = this.colors;
                var dst = this.object.geometry.colors;

                dst.push(src[a + 0], src[a + 1], src[a + 2]);
                dst.push(src[b + 0], src[b + 1], src[b + 2]);
                dst.push(src[c + 0], src[c + 1], src[c + 2]);

            },

            addUV: function (a, b, c)
            {

                var src = this.uvs;
                var dst = this.object.geometry.uvs;

                dst.push(src[a + 0], src[a + 1]);
                dst.push(src[b + 0], src[b + 1]);
                dst.push(src[c + 0], src[c + 1]);

            },

            addUVLine: function (a)
            {

                var src = this.uvs;
                var dst = this.object.geometry.uvs;

                dst.push(src[a + 0], src[a + 1]);

            },

            addFace: function (a, b, c, ua, ub, uc, na, nb, nc)
            {

                var vLen = this.vertices.length;

                var ia = this.parseVertexIndex(a, vLen);
                var ib = this.parseVertexIndex(b, vLen);
                var ic = this.parseVertexIndex(c, vLen);

                this.addVertex(ia, ib, ic);

                if (ua !== undefined)
                {

                    var uvLen = this.uvs.length;

                    ia = this.parseUVIndex(ua, uvLen);
                    ib = this.parseUVIndex(ub, uvLen);
                    ic = this.parseUVIndex(uc, uvLen);

                    this.addUV(ia, ib, ic);

                }

                if (na !== undefined)
                {

                    // Normals are many times the same. If so, skip function call and parseInt.
                    var nLen = this.normals.length;
                    ia = this.parseNormalIndex(na, nLen);

                    ib = na === nb ? ia : this.parseNormalIndex(nb, nLen);
                    ic = na === nc ? ia : this.parseNormalIndex(nc, nLen);

                    this.addNormal(ia, ib, ic);

                }

                if (this.colors.length > 0)
                {

                    this.addColor(ia, ib, ic);

                }

            },

            addLineGeometry: function (vertices, uvs)
            {

                this.object.geometry.type = 'Line';

                var vLen = this.vertices.length;
                var uvLen = this.uvs.length;

                for (var vi = 0, l = vertices.length; vi < l; vi++)
                {

                    this.addVertexLine(this.parseVertexIndex(vertices[vi], vLen));

                }

                for (var uvi = 0, l = uvs.length; uvi < l; uvi++)
                {

                    this.addUVLine(this.parseUVIndex(uvs[uvi], uvLen));

                }

            }

        };

        state.startObject('', false);

        return state;

    }

    //

    function OBJLoader(manager)
    {

        this.manager = (manager !== undefined) ? manager : THREE.DefaultLoadingManager;

        this.materials = null;

    }

    OBJLoader.prototype = {

        constructor: OBJLoader,

        load: function (url, onLoad, onProgress, onError)
        {

            var scope = this;

            var loader = new THREE.FileLoader(scope.manager);
            loader.setPath(this.path);
            loader.load(url, function (text)
            {

                onLoad(scope.parse(text));

            }, onProgress, onError);

        },

        setPath: function (value)
        {

            this.path = value;

        },

        setMaterials: function (materials)
        {

            this.materials = materials;

            return this;

        },

        parse: function (text)
        {

            console.time('OBJLoader');

            var state = new ParserState();

            if (text.indexOf('\r\n') !== -1)
            {

                // This is faster than String.split with regex that splits on both
                text = text.replace(/\r\n/g, '\n');

            }

            if (text.indexOf('\\\n') !== -1)
            {

                // join lines separated by a line continuation character (\)
                text = text.replace(/\\\n/g, '');

            }

            var lines = text.split('\n');
            var line = '', lineFirstChar = '';
            var lineLength = 0;
            var result = [];

            // Faster to just trim left side of the line. Use if available.
            var trimLeft = (typeof ''.trimLeft === 'function');

            for (var i = 0, l = lines.length; i < l; i++) {

                line = lines[i];

                line = trimLeft ? line.trimLeft() : line.trim();

                lineLength = line.length;

                if (lineLength === 0) continue;

                lineFirstChar = line.charAt(0);

                // @todo invoke passed in handler if any
                if (lineFirstChar === '#') continue;

                if (lineFirstChar === 'v') {

                    var data = line.split(/\s+/);

                    switch (data[0])
                    {

                        case 'v':
                            state.vertices.push(
								parseFloat(data[1]),
								parseFloat(data[2]),
								parseFloat(data[3])
							);
                            if (data.length === 8)
                            {

                                state.colors.push(
									parseFloat(data[4]),
									parseFloat(data[5]),
									parseFloat(data[6])

								);

                            }
                            break;
                        case 'vn':
                            state.normals.push(
								parseFloat(data[1]),
								parseFloat(data[2]),
								parseFloat(data[3])
							);
                            break;
                        case 'vt':
                            state.uvs.push(
								parseFloat(data[1]),
								parseFloat(data[2])
							);
                            break;

                    }

                }
                else if (lineFirstChar === 'f') {

                    var lineData = line.substr(1).trim();
                    var vertexData = lineData.split(/\s+/);
                    var faceVertices = [];

                    // Parse the face vertex data into an easy to work with format

                    for (var j = 0, jl = vertexData.length; j < jl; j++)
                    {

                        var vertex = vertexData[j];

                        if (vertex.length > 0)
                        {

                            var vertexParts = vertex.split('/');
                            faceVertices.push(vertexParts);

                        }

                    }

                    // Draw an edge between the first vertex and all subsequent vertices to form an n-gon

                    var v1 = faceVertices[0];

                    for (var j = 1, jl = faceVertices.length - 1; j < jl; j++)
                    {

                        var v2 = faceVertices[j];
                        var v3 = faceVertices[j + 1];

                        state.addFace(
							v1[0], v2[0], v3[0],
							v1[1], v2[1], v3[1],
							v1[2], v2[2], v3[2]
						);

                    }

                }
                else if (lineFirstChar === 'l') {

                    var lineParts = line.substring(1).trim().split(" ");
                    var lineVertices = [], lineUVs = [];

                    if (line.indexOf("/") === -1)
                    {

                        lineVertices = lineParts;

                    } else
                    {

                        for (var li = 0, llen = lineParts.length; li < llen; li++)
                        {

                            var parts = lineParts[li].split("/");

                            if (parts[0] !== "") lineVertices.push(parts[0]);
                            if (parts[1] !== "") lineUVs.push(parts[1]);

                        }

                    }
                    state.addLineGeometry(lineVertices, lineUVs);

                }
                else if ((result = object_pattern.exec(line)) !== null) {

                    // o object_name
                    // or
                    // g group_name

                    // WORKAROUND: https://bugs.chromium.org/p/v8/issues/detail?id=2869
                    // var name = result[ 0 ].substr( 1 ).trim();
                    var name = (" " + result[0].substr(1).trim()).substr(1);

                    state.startObject(name);

                }
                else if (material_use_pattern.test(line)) {

                    // material

                    state.object.startMaterial(line.substring(7).trim(), state.materialLibraries);

                }
                else if (material_library_pattern.test(line)) {

                    // mtl file

                    state.materialLibraries.push(line.substring(7).trim());

                }
                else if (lineFirstChar === 's') {

                    result = line.split(' ');

                    // smooth shading

                    // @todo Handle files that have varying smooth values for a set of faces inside one geometry,
                    // but does not define a usemtl for each face set.
                    // This should be detected and a dummy material created (later MultiMaterial and geometry groups).
                    // This requires some care to not create extra material on each smooth value for "normal" obj files.
                    // where explicit usemtl defines geometry groups.
                    // Example asset: examples/models/obj/cerberus/Cerberus.obj

                    /*
					 * http://paulbourke.net/dataformats/obj/
					 * or
					 * http://www.cs.utah.edu/~boulos/cs3505/obj_spec.pdf
					 *
					 * From chapter "Grouping" Syntax explanation "s group_number":
					 * "group_number is the smoothing group number. To turn off smoothing groups, use a value of 0 or off.
					 * Polygonal elements use group numbers to put elements in different smoothing groups. For free-form
					 * surfaces, smoothing groups are either turned on or off; there is no difference between values greater
					 * than 0."
					 */
                    if (result.length > 1)
                    {

                        var value = result[1].trim().toLowerCase();
                        state.object.smooth = (value !== '0' && value !== 'off');

                    } else
                    {

                        // ZBrush can produce "s" lines #11707
                        state.object.smooth = true;

                    }
                    var material = state.object.currentMaterial();
                    if (material) material.smooth = state.object.smooth;

                }
                else {

                    // Handle null terminated files without exception
                    if (line === '\0') continue;

                    throw new Error('THREE.OBJLoader: Unexpected line: "' + line + '"');

                }

            }

            state.finalize();

            var container = new THREE.Group();
            container.materialLibraries = [].concat(state.materialLibraries);

            for (var i = 0, l = state.objects.length; i < l; i++)
            {

                var object = state.objects[i];
                var geometry = object.geometry;
                var materials = object.materials;
                var isLine = (geometry.type === 'Line');

                // Skip o/g line declarations that did not follow with any faces
                if (geometry.vertices.length === 0) continue;

                var buffergeometry = new THREE.BufferGeometry();

                buffergeometry.addAttribute('position', new THREE.Float32BufferAttribute(geometry.vertices, 3));

                if (geometry.normals.length > 0)
                {

                    buffergeometry.addAttribute('normal', new THREE.Float32BufferAttribute(geometry.normals, 3));

                } else
                {

                    buffergeometry.computeVertexNormals();

                }

                if (geometry.colors.length > 0)
                {

                    buffergeometry.addAttribute('color', new THREE.Float32BufferAttribute(geometry.colors, 3));

                }

                if (geometry.uvs.length > 0)
                {

                    buffergeometry.addAttribute('uv', new THREE.Float32BufferAttribute(geometry.uvs, 2));

                }

                // Create materials

                var createdMaterials = [];

                for (var mi = 0, miLen = materials.length; mi < miLen; mi++)
                {

                    var sourceMaterial = materials[mi];
                    var material = undefined;

                    if (this.materials !== null)
                    {

                        material = this.materials.create(sourceMaterial.name);

                        // mtl etc. loaders probably can't create line materials correctly, copy properties to a line material.
                        if (isLine && material && !(material instanceof THREE.LineBasicMaterial))
                        {

                            var materialLine = new THREE.LineBasicMaterial();
                            materialLine.copy(material);
                            material = materialLine;

                        }

                    }

                    if (!material)
                    {

                        material = (!isLine ? new THREE.MeshPhongMaterial() : new THREE.LineBasicMaterial());
                        material.name = sourceMaterial.name;

                    }

                    material.flatShading = sourceMaterial.smooth ? false : true;

                    createdMaterials.push(material);

                }

                // Create mesh

                var mesh;

                if (createdMaterials.length > 1)
                {

                    for (var mi = 0, miLen = materials.length; mi < miLen; mi++)
                    {

                        var sourceMaterial = materials[mi];
                        buffergeometry.addGroup(sourceMaterial.groupStart, sourceMaterial.groupCount, mi);

                    }

                    mesh = (!isLine ? new THREE.Mesh(buffergeometry, createdMaterials) : new THREE.LineSegments(buffergeometry, createdMaterials));

                } else
                {

                    mesh = (!isLine ? new THREE.Mesh(buffergeometry, createdMaterials[0]) : new THREE.LineSegments(buffergeometry, createdMaterials[0]));

                }

                mesh.name = object.name;

                container.add(mesh);

            }

            console.timeEnd('OBJLoader');

            return container;

        }

    };

    return OBJLoader;

})();
